JP3277959B2 - Automatic transmission engagement control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to control of an automatic transmission mounted on a vehicle, and more particularly to control of an engagement speed of a friction element.

[0002]

2. Description of the Related Art Conventionally, among devices for controlling the engagement speed of a friction element, a device for controlling the engagement speed of a friction element when an engine brake is actuated, for example, is disclosed in
A backup pressure control device for an automatic transmission described in -80338 is known. This conventional device includes a means for detecting a vehicle speed at the time of selection to a manual range in an automatic transmission in which backup pressure is supplied to a friction element engaged when the automatic transmission range is selected to a manual range. Means for controlling the backup pressure based on a detection signal from the vehicle speed detection means, and supplying an optimal backup pressure according to the vehicle speed at the time of selection, and an emergency stop due to excessive backup pressure which may cause a shift shock. In this case, it is possible to prevent a delay in engagement due to a shortage of backup pressure, which causes a shortage of engine braking operation force.

[0003]

However, in the above-described conventional apparatus, the backup pressure, that is, the driving force for engaging the friction element is set based only on the vehicle speed. If the wheel shifts on a road surface with a low coefficient of friction, such as an icy road, when the back-up pressure is controlled at a high vehicle speed and the backup pressure is controlled to a high level, if the downshift is performed, the operating force of the engine brake will decrease. When the height is high, the wheels may slip further, and the stability of the vehicle may be reduced.

[0004] The present invention has been made in view of the above-mentioned conventional problems, and has as its object to prevent the wheels from slipping by optimizing the engagement speed.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, an engagement control device for an automatic transmission according to the present invention, as shown in FIG. A drive for engaging a behavior detecting means a for detecting a behavior, a road surface friction determining means b for determining a friction coefficient of a traveling road surface based on a signal from the behavior detecting means a, and a friction element d of the automatic transmission c. An engagement actuator e capable of changing the engagement speed, a road surface friction coefficient being equal to or less than a predetermined value and a vehicle speed being equal to or less than a predetermined value during the speed change by manual downshift.
In the above case, an engagement speed control means f for reducing the engagement speed is provided.

A part of the behavior detecting means a includes an accelerator depression amount detecting means for detecting an accelerator depression amount, a vehicle speed detecting means for detecting a vehicle speed, and a select position detecting means for detecting a select position of the automatic transmission. Means for controlling the engagement speed based on the input from the behavior detecting means a, the select position is selected from a high gear to a low gear, and the accelerator pedal depression amount is equal to or less than a predetermined value. When it is determined that the operation is
Control may be performed . Further, the road surface friction determining means b may determine the rotational deceleration of the drive wheels of the vehicle during the operation of the engine brake, and determine that the road surface has a lower friction coefficient as the deceleration increases.

Further, the road surface friction determining means b may determine the rotational speeds of the driving wheels and the non-driving wheels of the vehicle, and may determine that the road surface with lower friction has a larger difference in speed between them.

A part of the behavior detecting means a includes a vehicle body acceleration detecting means for detecting a behavior related to the longitudinal acceleration / deceleration of the vehicle body, and a wheel rotational speed detecting means for detecting a behavior related to the rotational speed of the driving wheels. Means, and the road surface friction determining means b includes a calculated acceleration / deceleration obtained by calculation based on an input from the wheel rotation speed detecting means, and an actual vehicle body obtained based on an input from the vehicle body acceleration / deceleration detecting means. The actual acceleration / deceleration, which is the acceleration / deceleration of the vehicle, may be determined, and the larger the difference between the two, the more the road surface having lower friction may be determined.

[0009]

In a manual downshift, when the road surface friction determining means detects a road surface having a low friction coefficient lower than a predetermined value and the vehicle speed is lower than a predetermined value , the engagement speed detecting means decreases the engagement speed. controls to. Therefore, at the time of engine braking or acceleration, the engagement speed is reduced, causing slippage in the friction element,
Control can be performed to prevent the occurrence of slippage between the wheel and the road surface.

Further, in the apparatus of claim 2 wherein the select position of the automatic transmission is selected from high gear to low gear and engine <br/> emissions braking action since the depression amount of the accelerator is below a predetermined Time , the engagement speed control is performed.
U. As a result, it is possible to prevent a slip from occurring between the wheel and the road surface when the engine brake operates.

[0011]

An embodiment of the present invention will be described with reference to the drawings.

FIG. 2 is a structural explanatory view showing the outline of the structure of an automatic transmission AT to which the engagement control device according to the first embodiment of the present invention is applied, wherein T / C denotes a torque converter, O / P Is an oil pump, IN is an input shaft, B / B is a band brake, R / C is a reverse clutch, H / C is a high clutch, S _F is a front sun gear, P _F is a front pinion gear, R _F is a front internal gear, C _F
The front carrier, S _R is rear sun gear, P _R is the rear pinion gear, R _R is the rear internal gear, C _R is the rear carrier, F / C is the forward clutch, F / OC forward one-way clutch, O / C is overrun clutch, L / OC is row one way clutch, L & R / B
Is a low and reverse brake, PP is a parking pole, PG is a parking gear, and OUT is an output shaft. Note that this configuration is the same as the related art and is well known, and therefore detailed description is omitted.

Each friction element B /
B, R / C, H / C, F / C, F / OC, O / C, L
& R / B are engaged by the combinations shown in the fastening operation table of Table 1 below to thereby provide other friction elements F / O.
Combined with C, L / OC operation, forward 4th speed, reverse 1
A high gear can be obtained. In the figure, ○, ◎,
The marks of ●, △, × indicate the engaged state, respectively, ◎ indicates that the accelerator is opened at 1/16 of the accelerator opening to obtain the engine braking effect, ● indicates that the engine is operating in acceleration, Engaged but not contributing to power transmission, x indicates engagement at accelerator opening 1/16 but no contribution to engine braking. * 1 indicates that the operation is limited to the power mode, * 2 indicates that the brake band is not fastened, and * 3 indicates that the brake band is fastened.

[0014]

[Table 1] Each of the above frictional elements B / B, R / C, H / C, F / C, F
The operation of / OC, O / C, L & R / B is controlled by the operation of a control valve CV provided below the automatic transmission A / T shown in FIG. 3, and the operation of the control valve CV is controlled. To this end, a first shift solenoid 1, a second shift solenoid 2, an overrun clutch solenoid 3, a lock-up solenoid 4, and a line pressure solenoid 5 are provided. The driving of these solenoids 1 to 5 is controlled by the A / T control unit 6. The signal to the line pressure solenoid 5 is output via the dropping register 7.

That is, the A / T control unit 6
Is an idle switch 8 for detecting the full closing of the throttle valve, and 1 / th of the throttle valve,
A full throttle switch 9 for detecting two or more openings, a throttle sensor 10 for detecting the throttle opening, an engine rotation sensor 11 for detecting the number of revolutions of the engine E, an inhibitor switch 12 for detecting the position of a manual lever (not shown), A temperature sensor 13 for detecting the oil temperature in the transmission A / T, a first vehicle speed sensor 14 provided on an output shaft OUT of the automatic transmission A / T for detecting a vehicle speed, and a spare second motor with a built-in meter (not shown). 2 vehicle speed sensor 15,
Power switch 1 for manual switching provided in vehicle interior
6, a kick-down switch 17 for detecting a fully opened state of an accelerator pedal (not shown) is provided, and in this embodiment, a drive wheel sensor 1 for detecting a rotational speed of a drive wheel (not shown)
8 are provided.

The first and second shift solenoids 1 and 2 are driven to select a transmission gear according to the running state of the vehicle. The overrun clutch 3
Is for controlling the engine braking effect according to the running state of the vehicle. When OFF, the line pressure is supplied to the overrun clutch O / C to be engaged and the engine brake is applied, while when ON, the overrun clutch O / C is applied. The line pressure is not supplied and the engine is not engaged, and the engine brake does not operate. The lock-up solenoid 4 regulates the lock-up pressure according to the running condition of the vehicle. The line pressure solenoid 5 regulates the discharge pressure of the oil pump O / P to a pressure corresponding to the traveling of the vehicle. That is, normally, the duty ratio is set so as to form the optimum line pressure based on the output of the throttle sensor 10. Control (ON-OF
Control of the ratio of the ON time of F switching).

In this embodiment, during the operation of the engine brake, the engagement pressure (line pressure) of the overrun clutch O / C is changed according to the vehicle speed V and the road surface friction coefficient μ (hereinafter, the road surface friction coefficient is referred to as road surface μ). By controlling, the engagement speed of the overrun clutch O / C is made variable.
That is, FIG. 4 shows a rising characteristic of the engagement pressure P at the time of engagement of the overrun clutch O / C. As shown in FIG. And the rise at the start of engagement is very slow, as shown in
There are three types of characteristics: a characteristic that increases the engagement pressure as the vehicle speed decreases, and a characteristic that the rise at the start of engagement is medium and then increases as the vehicle speed decreases. are doing. The above-mentioned overrun clutch O /
The fastening pressure of C is regulated by driving the line pressure solenoid 5, and the line pressure solenoid 5 corresponds to an engagement actuator in the claims.

Next, control of the engagement speed (engagement pressure) of the overrun clutch O / C will be described with reference to the flowchart of FIG.

This control is started when the manual lever selects the second speed or the first speed from the D range. Step S1 is to determine whether or not a shift from a high gear to a low gear is performed by this selection. It is a step for proceeding to step S2 if YES and proceeding to the next other flow if NO.

In step S2, it is determined whether or not the throttle opening θ is equal to or smaller than a predetermined value θ ₀ based on the output from the throttle sensor 10. If YES, the process proceeds to step S3, and N
O is a step to proceed with a normal flow. The predetermined value θ ₀ is set to a throttle opening (for example, 1/16 of full opening) at which a sufficient engine braking action can be obtained in the selected low-speed gear, and is a sufficiently small opening.

Step S3 is a step for calculating the acceleration / deceleration G of the drive wheel based on the output from the drive wheel sensor 18.

Step S4 is a step of judging a road surface friction coefficient μ based on the acceleration / deceleration G obtained in the previous step S3, that is, when the acceleration G indicates a deceleration equal to or more than a predetermined value, the road surface friction coefficient It is determined that μ is a low road surface (hereinafter referred to as a low μ road), and processing is performed with μ = α. Here, α is a small value indicating a low μ road. Further, the part that makes the determination in step S4 corresponds to the road surface friction determining means in the claims.

Step S5 is a step for calculating the vehicle speed V based on the output of the first vehicle speed sensor 14.

The step S6, the road surface friction coefficient mu was determined in step S4 is equal to or less than a predetermined value mu _0, the process proceeds to step S7 YES, a step S8 is NO
The predetermined value μ ₀ is a value larger than α. Therefore, if it is determined in step S4 that the road surface is a low μ road, the process proceeds to step S7, and if not, the process proceeds to step S7. The process proceeds to step S8.

[0025] Step S7 the vehicle speed V is equal to or less than a predetermined value V _0, the process proceeds to step S9 YES, a
If NO, the process proceeds to step S10. The predetermined value V ₀ is a value for determining whether a high-speed driving, for example, set to a value in the range of 30 to 40 km / h.

In step S8, a similar determination is made and YES
Proceeds to step S9, and proceeds to step S11 if NO.

In step S9, the characteristic shown in FIG. 4 is selected, and the drive of the line pressure solenoid 5 is controlled based on this characteristic, that is, the overrun clutch O / C.
This is a step of performing drive control to increase the engagement speed of the vehicle at the start of the engagement and thereafter increase the vehicle speed V as the vehicle speed V decreases. By the way, this characteristic is selected when the vehicle speed is low on a low μ road or when the vehicle speed is low on a high μ road.

In step S10, the characteristic of FIG. 4 is selected, and the drive of the line pressure solenoid 5 is controlled based on this characteristic, that is, the overrun clutch O / C.
Is a step in which drive control is performed so that the engagement speed is very slow at the start of engagement, and then increases as the vehicle speed V decreases. Incidentally, this characteristic is selected when the vehicle speed is high on a low μ road.

Step S11 is to select the characteristic of FIG. 4 and to control the drive of the line pressure solenoid 5 based on this characteristic, that is, the overrun clutch O / C.
This is a step in which drive control is performed so that the engagement speed is medium at the start of the engagement, and thereafter increased as the vehicle speed V decreases. Incidentally, this characteristic is selected when the vehicle speed is high on a high μ road. Step S5 described above
The part that performs the determination and processing of S11 to S11 corresponds to the engagement speed control means in the claims.

Therefore, when the engine lever is obtained by operating the manual lever, when the vehicle speed V is lower than the predetermined value V ₀ , regardless of the road surface friction coefficient μ,
The line pressure control is performed based on the characteristics shown in FIG. 4 to control the engagement speed of the overrun clutch O / C faster. In this case, even when traveling on a low μ road, since the vehicle speed V is low,
The wheels do not slip. Further, during high speed running than the vehicle speed V is a predetermined value V _0, in the high μ road, performs line pressure control based on the characteristics of the FIG. 4, an overrun clutch engagement speed of the slower than during the low speed traveling O / C is engaged. As described above, when the vehicle is traveling at high speed on a high μ road, there is no problem in slipping of the wheels without reducing the engagement speed, but the engagement speed is slightly reduced in order to reduce the shift shock. On the other hand, when the vehicle is running on a low μ road at high speed, the line pressure control is performed based on the characteristics shown in FIG. 4, and the engagement speed of the overrun clutch O / C is further reduced as compared with the above-described high speed road running on a high μ road. Since the engagement speed is reduced in this manner, the wheels can be prevented from slipping even on a low μ road, and traveling stability can be ensured.

Next, a second embodiment of the present invention will be described.

FIG. 6 is a block diagram showing a main part of the apparatus according to the second embodiment. In this embodiment, a driven wheel sensor 19 for detecting the rotational speed of a driven wheel is provided in addition to a driving wheel sensor 18. This is an example in which a road surface μ judgment different from that of the first embodiment is performed. In the figure, reference numeral 20 denotes a slip amount calculating unit for calculating a slip amount based on signals from the driving wheel sensor 18 and the driven wheel sensor 19, and reference numeral 21 denotes a slip amount calculating unit 20.
A road friction determining unit for determining a road surface μ based on the calculation result of the above; a select position determining unit for determining a select position based on a signal from the inhibitor switch;
Is a vehicle speed calculator that calculates the vehicle speed V based on a signal from the first vehicle speed sensor 14, 24 is an accelerator depression amount calculator that calculates the accelerator depression amount based on a signal from the throttle sensor 10, and 25 is each determination unit 21. , 22 and arithmetic unit 2
3 and 24, each of which determines an engagement speed based on signals from the AT and the AT according to the first embodiment.
2 shows a portion that performs signal processing inside the control unit 6.

The operation of the above configuration will be described with reference to the flowchart of FIG. Steps having the same contents as in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

In step S21, the slip amount calculating section 20
Is the step of determining the slip amount L. In the case of the present embodiment, the driving wheel rotation speed N ₁ obtained from the output of the driving wheel sensor 18 and the driven wheel rotation speed N obtained from the output of the driven wheel sensor 19 the difference between ₂ calculates the slip amount L (| L | = | N 1 -N 2 |) is a step. Steps S22, S23, and S24 are steps for determining the road surface μ by the road surface friction determination unit 21.
Slip amount L is equal to or a predetermined value L ₀ or at 22, the routine proceeds to step S23 YES, a road surface μ is treated as the alpha (Note, alpha is low, the low μ road NO, the process proceeds to step S24 with NO, and the road surface μ is processed as β (β is a high value, which corresponds to determining that the road is a high μ road). Do).

Steps S6 to S11 are for selecting the line pressure characteristic in accordance with the road surface μ in the engagement speed switching calculating section 25 in the same manner as in the first embodiment. In step S6, the road surface μ is set to the predetermined value μ _0. It is determined whether or not the following conditions are satisfied. The predetermined value μ ₀ has a relationship of β> predetermined value μ ₀ > α.

Based on the above configuration, as in the first embodiment, when the vehicle is running at a high speed on a low μ road, the overrun clutch O / C
Can be reduced to prevent the wheels from slipping.

Next, a third embodiment of the present invention will be described.

FIG. 8 is a block diagram showing a main part of the third embodiment. In this embodiment, an acceleration / deceleration sensor 26 for detecting the acceleration / deceleration of the vehicle body in the front-rear direction is provided in place of the drive wheel sensor 18. This is an example in which a road surface μ judgment different from that of the first embodiment is performed. In the figure, reference numeral 27 denotes an acceleration / deceleration calculation unit. The same components as those in the first embodiment or the second embodiment are denoted by the same reference numerals, and description thereof will be omitted.

The operation of the above configuration will be described with reference to the flowchart of FIG. Steps having the same contents as those in the first embodiment or the second embodiment are denoted by the same reference numerals, and description thereof is omitted.

In step S31, the acceleration / deceleration calculating section 27 determines an engine load based on the selected position, the vehicle speed V, and the accelerator pedal depression amount, and further calculates a calculated acceleration / deceleration which is a calculated acceleration / deceleration of the vehicle body from the engine load. a step of calculating a G _a.

Steps S32, S33, S23, S24
Is a step for performing a determination of the road surface mu, in step S32, the computation acceleration G _A obtained from acceleration speed calculating unit 27, from the actual acceleration G _T obtained from the acceleration sensor 26, Find the degree of slip L _B (| L _B |
_{= | G A -G T |)} . The next, at step S33, the slip degree L _B is equal to or a predetermined value L _B0 above,
If the determination is YES, the process proceeds to step S23 to process the road surface μ as α, and if the determination is NO, the process proceeds to step S24 to process the road surface μ as β (α, β and the predetermined value μ _{0 in} step S6 are , The same values as in the first and second embodiments).

Based on the above configuration, as in the first embodiment, the overrun clutch O / C
Can be reduced to prevent the wheels from slipping.

Although the embodiment has been described above, the specific configuration is not limited to this embodiment, and any change in the design without departing from the gist of the present invention is also included in the present invention. For example, in the embodiment, the control for preventing the slip of the wheel at the time of the engine braking has been described. However, the control may be applied to the control for preventing the slip of the wheel at the time of starting or accelerating. In this case, for example, in steps S21 to S24 of the second embodiment, the road surface μ is obtained from the slip amount L. For example, if the throttle opening θ is equal to or more than a predetermined value and the road surface μ is equal to or less than the predetermined value, the line pressure is determined. Of the frictional element to be engaged at that time is controlled so as to slow down the rise of the frictional element.

[0044]

As described above, in the engagement control device for an automatic transmission according to the present invention, the manual downshift
Road surface friction coefficient during shifting by preparative predetermined or less and the vehicle speed
Is greater than or equal to a predetermined value, the engagement speed control means for reducing the engagement speed is provided, so when shifting while traveling on a road surface with a low friction coefficient, the engagement speed is reduced, It is possible to prevent a slip from occurring between the wheel and the road surface by causing a slip in the friction element, thereby obtaining an effect of improving running stability.

Further, in the invention of claim 2, select position is selected from a high gear to the low gear, and, when the depression amount of the accelerator was time and decipher engine braking from being below a predetermined In addition, since the engagement speed control is performed , it is possible to prevent the wheels from slipping particularly when the engine brake is actuated, thereby improving running stability.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to claims showing an engagement control device for an automatic transmission according to the present invention.

FIG. 2 is a structural explanatory view showing a structure of an automatic transmission to which an engagement control device for an automatic transmission according to a first embodiment of the present invention is applied.

FIG. 3 is a configuration explanatory diagram showing a configuration related to a portion for controlling the first embodiment apparatus.

FIG. 4 is a line pressure characteristic diagram of the first embodiment apparatus.

FIG. 5 is a flowchart showing a control flow of the first embodiment.

FIG. 6 is a block diagram showing an engagement control device for an automatic transmission according to a second embodiment of the present invention.

FIG. 7 is a flowchart illustrating a control flow of the second embodiment apparatus.

FIG. 8 is a block diagram showing an engagement control device for an automatic transmission according to a third embodiment of the present invention.

FIG. 9 is a flowchart showing a control flow of the third embodiment.

[Explanation of symbols]

 a behavior detecting means b road surface friction determining means c automatic transmission d friction element e engagement actuator f engagement speed control means

Continuation of front page (56) References JP-A-2-89846 (JP, A) JP-A-62-80338 (JP, A) JP-A-3-24360 (JP, A) JP-A-60-215434 (JP) JP-A-3-153959 (JP, A) JP-A-63-1842 (JP, A) JP-A-4-43832 (JP, A) JP-A-4-107357 (JP, A) 63-78749 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/40-63/48

Claims (5)

(57) [Claims] 1. Behavior detecting means for detecting a behavior related to running and driving of a vehicle; road surface friction determining means for determining a friction coefficient of a running road surface based on a signal from the behavior detecting means; An engagement actuator capable of changing the engagement speed by performing driving for engaging the elements; and an engagement speed when a road surface friction coefficient is equal to or less than a predetermined value and a vehicle speed is equal to or more than a predetermined value at the time of shifting by manual downshifting.
An engagement control device for an automatic transmission, comprising: engagement speed control means for delaying the engagement. 2. As the behavior detecting means, there are an accelerator depression amount detecting means for detecting an accelerator depression amount, a vehicle speed detecting means for detecting a vehicle speed, and a select position detecting means for detecting a select position of the automatic transmission. However, based on the input from the behavior detecting means, the engagement speed control means selects the select position from the high gear to the low gear and determines that the accelerator pedal depression amount is equal to or less than a predetermined value, so that it is during engine braking. When determined, the engagement
The engagement control device for an automatic transmission according to claim 1, wherein the engagement control device performs speed control . 3. The road surface friction determining means determines a rotational deceleration of a driving wheel of a vehicle when an engine brake is applied, and determines that the road surface has a lower friction coefficient as the deceleration is larger. The engagement control device for an automatic transmission according to claim 2. 4. The road surface friction determining means determines a rotational speed of a driven wheel and a non-driven wheel of a vehicle, and determines that the road surface having lower friction is determined as the difference between the two is larger. The engagement control device for an automatic transmission according to claim 1 or 2, wherein: 5. A vehicle body acceleration detecting means for detecting a behavior related to a longitudinal acceleration / deceleration of a vehicle body, a wheel rotational speed detecting means for detecting a behavior related to a rotational speed of a driving wheel, The road surface friction determining means calculates and calculates the acceleration / deceleration based on the input from the wheel rotation speed detecting means and the actual acceleration / deceleration which is the actual acceleration / deceleration of the vehicle body obtained based on the input from the vehicle acceleration / deceleration detecting means. The engagement control device for an automatic transmission according to claim 1 or 2, wherein the larger the difference between the two is, the more it is determined that the road surface has lower friction.